Changing air flow direction on air-cooled electronic devices

ABSTRACT

Embodiments of the present disclosure include systems and methods for controlling the direction of cooling air flow across components of an electronic devices. An air-cooled electronic device includes: an air flow generator that is able to generate air flow in either first or second direction across the device; a sensor that measures first and second temperatures of air in the device when the air flows in the first and second directions, respectively; and a controller coupled to the mechanism and the sensor. The controller compares the first temperature to the second temperature and controls the air flow generator to generate the air flow in one of the first and second directions based on comparison of the first temperature to the second temperature.

TECHNICAL FIELD

The present invention relates to controlling the temperature ofelectronic devices, more particularly, to systems and methods forcontrolling the direction of air flow across components of air-cooledelectronic devices.

DESCRIPTION OF THE RELATED ART

There often arises a need to control the direction of the air flowacross components of air-cooled electronics. It is quite common when anair-cooled device is installed in an equipment rack (or, shortly, rack)with other air-cooled electronics in a computer room or data center.FIG. 1 shows a schematic diagram 100 of conventional racks in anair-conditioned computer room. As depicted, two rows of racks, 104 and106 are located on a floor 102, where each rack (e.g., 106 a) mayaccommodate multiple electronic devices (or, equivalently, equipment)(e.g., 106 a 1-106 a 3). An air conditioning (AC) unit (not shown inFIG. 1) may send cold air through the duct 140 under the floor 102.Then, as indicated by arrows 108, the cold air exits the duct 140through the vents 103 on the floor.

For efficiency in cooling the racks 104 and 106, the preferred method ofracking the equipment is to pull in cooler air from the aisle 150 anddischarge warmer air to the adjacent aisle 152 (or 154), as indicated bythe arrows 110 (or 111). This method may be preferred, but extremelydifficult to achieve due to many factors standing in the way of propercooling of equipment: (1) when a network switch is installed in a rack,there may be usually more concern about which direction the devicesshould be facing than which direction the air flow should be for propercooling. This is because it is common for a rack to have over a hundredcables coming out of one or both sides of the rack (the majority of themfrom network switches), making cable management another substantialissue that is easier to both see and quantify. It is often desirable forthe user to position the equipment into the rack to make cabling easierin the present and future, regardless of the impact it has on coolingand cooling costs. (2) The user may not think about the air flowdirection until long after having installed the equipment into the rack.(3) The equipment may be already in place and the user may think it isnot feasible to re-position the equipment. (4) There may be a need toschedule company downtime in order to make the necessary equipmentchanges. (5) In cases where there are no hot/cold aisles, the user maynot take the time to find out which direction the air flow should be.(6) Changes in the conditions of ambient temperatures surrounding theequipment can occur when additional equipment is installed nearby, whena vent/duct is inadvertently blocked, when furniture or other objectsare moved, when an air conditioner fails, etc.

For the purpose of illustration, the device/equipment 106 a 2 is assumedto be installed in such a manner that the device 106 a 2 takes warm airin the aisle 154 and discharges hot air into the aisle 150, as indicatedby the arrow 112. The hot air discharged from a device should be on itsway back to the AC unit to be re-cooled; instead, as indicated by thearrow 114, the hot air from the device 106 a 2 continues to circulateback to the racks 106 a-106 e (and/or 104 a-104 e), causing drasticinefficiencies in cooling. What further can exacerbate the problem isthat the electronic industry is manufacturing increasingly densecomponents that are more sensitive to temperature.

If the device 106 a 2 has a mechanism to reverse the air flow, thecooling efficiency would increase significantly. There is currently noeasy or fast way to reverse the air flow 112. On equipment already in aproduction environment, few users are willing to order new fans that canreverse air flow and wait on them to ship just to reverse the air flowat a later data. In some cases, the new fans may not be installed in thedevices/racks for one or more of reasons set forth above. As such, thereis a need for systems and methods for control the direction of air flowacross a device/equipment of air-cooled electronics.

BRIEF DESCRIPTION OF THE DRAWINGS

References will be made to embodiments of the present disclosure,examples of which may be illustrated in the accompanying figures. Thesefigures are intended to be illustrative, not limiting. Although thedisclosure is generally described in the context of these embodiments,it should be understood that it is not intended to limit the scope ofthe disclosure to these particular embodiments. Items in the figures maynot be to scale.

FIG. 1 shows a conventional arrangement of racks in an air-conditionedcomputer room.

FIGS. 2A and 2B show a device that has a control unit to manuallycontrol the direction of air flow according to embodiments of thepresent disclosure.

FIGS. 3A-3C show partial cutaway views of a device that has a controlunit to automatically control the direction of air flow according toembodiments of the present disclosure.

FIG. 4 shows a flowchart of an illustrative process for automaticallycontrolling the direction of air flow across a device according toembodiments of the present disclosure.

FIG. 5 shows a computer system according to embodiments of the presentdisclosure.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the following description, for purposes of explanation, specificdetails are set forth in order to provide an understanding of thedisclosure. It will be apparent, however, to one skilled in the art thatthe disclosure can be practiced without these details. Furthermore, oneskilled in the art will recognize that embodiments of the presentdisclosure, described below, may be implemented in a variety of ways,such as a process, an apparatus, a system, a device, or a method on atangible computer-readable medium.

Elements/components shown in diagrams are illustrative of exemplaryembodiments of the disclosure and are meant to avoid obscuring thedisclosure. It shall also be understood that throughout this discussionthat components may be described as separate functional units, which maycomprise sub-units, but those skilled in the art will recognize thatvarious components, or portions thereof, may be divided into separatecomponents or may be integrated together, including integrated within asingle system or component. It should be noted that functions oroperations discussed herein may be implemented as components/elements.Components/elements may be implemented in software, hardware, or acombination thereof.

Furthermore, connections between components or systems within thefigures are not intended to be limited to direct connections. Rather,data between these components may be modified, re-formatted, orotherwise changed by intermediary components. Also, additional or fewerconnections may be used. It shall also be noted that the terms “coupled”“connected” or “communicatively coupled” shall be understood to includedirect connections, indirect connections through one or moreintermediary devices, and wireless connections.

Furthermore, one skilled in the art shall recognize that: (1) certainsteps may optionally be performed; (2) steps may not be limited to thespecific order set forth herein; and (3) certain steps may be performedin different orders; and (4) certain steps may be done concurrently.

Reference in the specification to “one embodiment,” “preferredembodiment,” “an embodiment,” or “embodiments” means that a particularfeature, structure, characteristic, or function described in connectionwith the embodiment is included in at least one embodiment of thedisclosure and may be in more than one embodiment. The appearances ofthe phrases “in one embodiment,” “in an embodiment,” or “in embodiments”in various places in the specification are not necessarily all referringto the same embodiment or embodiments. The terms “include,” “including,”“comprise,” and “comprising” shall be understood to be open terms andany lists that follow are examples and not meant to be limited to thelisted items. Any headings used herein are for organizational purposesonly and shall not be used to limit the scope of the description or theclaims.

Furthermore, the use of certain terms in various places in thespecification is for illustration and should not be construed aslimiting. A service, function, or resource is not limited to a singleservice, function, or resource; usage of these terms may refer to agrouping of related services, functions, or resources, which may bedistributed or aggregated.

FIG. 2A shows a device 206 installed in a rack 202, where the device 206has a control unit to manually control the direction of air flowaccording to embodiments of the present disclosure. As depicted, one ormore devices 204 and 206 are installed in the rack 202, where eachdevice may include various air-cooled electronic components. For thepurpose of illustration, only two devices are shown in FIG. 2A. However,it should be apparent to those of ordinary skill in the art that othersuitable number of devices may be installed in the rack 202.

In embodiments, the rack 202 may be located inside an air-conditionedcomputer room, where the hot aisle 230 and cold aisle 232 are separatedby the rack space 234. During operation, the device 204 may have one ormore fans (not shown in FIG. 2A) that pull in cold air from the coldaisle 232 (as indicated by the arrows 210) and discharge hot air to thehot aisle 230 (as indicated by the arrows 212) after the cold airextracts heat energy from the electronic components inside the device204. In embodiments, each of the devices in the rack 202 has one or morefans for generating the air flows 210 and 212. However, it should beapparent to those of ordinary skill in the art that each device may haveother suitable type(s) of mechanism (or, air flow generator) that cangenerate the air flow across the device.

In embodiments, positioning of the devices (e.g. 206) with respect tothe cool aisle 232 may be determined by various factors. For instance,the user may consider the efficient cabling of costly wires, from thefront to the back of the rack 202, over the top of the rack, aroundcorners or through the rack itself (cables are not shown in FIG. 2A).Upon considering these factors, the device 206 may be positioned in therack 202 in such way that the fans of the device 206 pulls in hot airfrom the hot aisle 230 (as indicated by the arrows 218) and dischargesheated air to the cold aisle 232 (as indicated by the arrows 220),

If the device 206 pulls in hot air from the hot aisle 230 and dischargesheated air to the cold aisle 232, a portion of the heated air 220 may bemixed with the cold air and pulled into the device 204, as indicated bythe arrows 214. Likewise, a portion of the hot air 212 discharged by thedevice 204 may be pulled into the device 206 without having a chance tocondition and cool, as indicated by arrows 216. The arrows 214 and 216show the bidirectional air flow in and around the rack caused by thedevice 206. The bidirectional air flow may reduce the cooling efficiencyof the rack 202 and, in some cases, cause damages to the electricalcomponents of the devices 204 and 206.

In embodiments, the device 206 may have a control unit to change thedirection of air flow across the device 206, where the control unitincludes one or more interfaces, switches, controls, or buttons 207. Itshall be noted that, in embodiments, the one or more interfaces,switches, controls, or buttons may be an actual interface, switch,control, or button or may be a soft (i.e., virtual) interface, switch,control, or button. In embodiments, the user may check the direction ofthe air flow across each device, and, if a device pulls in hot air fromthe hot aisle 230, the user may push the button of the control unit 207to reverse the direction of the air flow, to thereby remove thebi-directional air flow around the rack 202.

In embodiments, the control unit to control the air flow direction mayhave a controller that is electrically coupled to the button 207 andreverses the fans when the user presses the button 207. In embodiments,the controller may be a processor coupled to the button 207 and thefans. In response to the “Press” signal from the button 207, theprocessor may send a signal to the fans in order to change (or reverse)the rotational direction of the fans. In embodiments, to avoidaccidental touch/press of the button 207, the user needs to push thebutton 207 for a preset period of time (such as 10 seconds) before thecontrol unit reverses the air flow. In embodiments, the button 207 maybe used to reverse the air flow after the power has been applied to thedevice 206. In embodiments, the button 207 may be used to reverse theair flow after the power has been applied to the device 206 and thedevice 206 has been in normal operation for a while. Again, the button207 may need to be pressed for a preset time period to ensure that it isnot pressed accidentally.

FIG. 2B shows the directions of air flows from the devices 204 and 206,where the user has reversed (or switched) the direction of air flowacross the device 206 by operating the button 207. As depicted, theentire air flow across the rack 202 is unidirectional, i.e., both thedevices 204 and 206 in the rack 202 pull in cold air from the cold aisle232 in only one direction (as indicated by arrows 250) and discharge thewarm air to the hot aisle 230 in only one direction (as indicated byarrows 252). Since the circulation of air in and around the rack due tothe bidirectional air flow is removed, there would be no mixing betweenthe cold air and hot air in the cold aisle 232, resulting in enhancedefficiency in cooling the devices in the rack 202.

It is noted that the control unit 207 allows the user to change thedirection of the air flow without changing the position of the device206 or the rack 202. Unlike the conventional systems where the user issometimes forced to give up the efficient cabling in order to achieveefficient air flow, the user of the embodiments is able to achieve theideal flow pattern in FIG. 2B without compromising the efficiency incabling.

In embodiments, one or more sensors, such as lab thermometers, may beplaced around racks (e.g., 270) and/or in the rack (e.g., 272) todetermine ambient temperature. Based on the readings of thethermometers, the user may decide whether to change the air flow acrosseach device for proper air flow around the rack 202. In FIG. 2A, onlythree sensors are shown. However, it should be apparent to those ofordinary skill in the art that other suitable number of sensors may beplaced in and around the rack 202. Also, it should be apparent to thoseof ordinary skill in the art that the sensors are connected to asuitable controller that controls the sensors and provides theinformation of the measured ambient temperatures to the user.

In embodiments, the control unit of the device 206 may include athermometer (e.g. 272) coupled to the controller. The controllercontinuously monitors the signals from the thermometer and sends awarning signal, such as simple network management protocol (SNMP) trap,each time the temperature goes beyond a preset threshold and prompts theuser to monitor the situation that may lead to reversing the air flow.

Proper air flow in many electronic devices is crucial in order tomaintain safe temperatures that will not cause errors in programs on thedevice or physical damage to the device itself. Electronic components inthe electronic devices are becoming smaller and more dense on circuitcard assemblies, backplane assemblies, and printed circuit boardassemblies. These smaller components are more sensitive to hightemperatures and require enhanced cooling techniques.

To properly cool the electronic components, as discussed above inconjunction with FIGS. 2A-2B, the user may need to check the air flowdirection of each device and, if necessary, the user has to push thebutton 207 to manually change (or switch) the air flow direction. Insome cases, operation of the manual button 207 may not be convenient tothe user. For instance, if there is no hot/cold aisle, the user may notbe able to decide which direction the air needs to go. In anotherexample, it may be possible that the ambient temperature on one or moresides of the equipment changes due to newly installed equipment nearby,an AC malfunction, alterations in ambient air flow, etc. In such cases,the user may not be able to determine the proper air flow directionquickly. In yet another example, large computer rooms and data centershaving a large number of racked equipment may require a considerableamount of time and effort to manually control all devices.

In embodiment, where the operation of the manual button 207 isinconvenient, the manual button 207 may be replaced with a mechanismthat automatically changes the direction of air flow. FIG. 3A shows apartial cutaway view of a device that has a control unit toautomatically control the direction of air flow according to embodimentsof the present disclosure. As depicted in FIG. 3A, the electronicallyair-cooled device (or, shortly, device) 300 may include: a vent 304having one or more openings for air flow; one or more fans 306 forgenerating air flow through the device 300; and a control unit 305coupled to the fans 306. The control unit 305 may include: athermometer/thermocouple that measures the temperature of the air insidethe device 300; and a controller that operates the thermometer and thefans 306.

FIG. 4 shows a flowchart 400 of an illustrative process forautomatically controlling the direction of air flow through the device300 according to embodiments of the present disclosure. At step 402, asdepicted in FIG. 3B, the fans 306 may pull in air from the front side332 through the vent 304 (as indicated by the arrows 310) and dischargethe air to the rear side 330, where the front side 332 and the rear side330 are separated by the device space 334. The control unit 305 maymeasure the first temperature of the air while the fans 306 aredischarging the air to the rear side 312 and record the measuredtemperature.

At step 404, as depicted in FIG. 3C, the control unit 305 may reversethe fans 306 (i.e., switch the air flow direction) so that the fans 306may pull in air from the rear side 330 (as indicated by the arrows 320)and discharge the air to the front side 332 through the vent 304. Thecontrol unit 305 may measure and record the second temperature of theair while the fans 306 are discharging the air to the front side 332.

At step 406, the control unit 305 may compare the first temperature tothe second temperature. Then, at step 408, based on the comparison, thecontrol unit 305 may cause the fans 306 to blow the air only in thedesired direction during the normal operation of the device 300. In thepresent example, the desired direction may be the direction that pullsin cold air from the front side 332 since the front side 332 is thecolder aisle, as shown in FIG. 3B.

In embodiments, the processes in the flow chart 400 may be performedimmediately after power is applied to the device 300. Alternatively, inembodiments, the process may be performed on a regular basis and changeair flow direction as needed without cycling power on the device 300.Optionally, the control unit 305 may include an agent that sends asimple network management protocol (SNMP) trap each time the fans 306change the flow direction and notify the user of a change in the ambienttemperature surrounding the device 300. In embodiments, the agent may behardware, software, firmware, or combination thereof, included in thecontrol unit 305. In embodiments, the processes in the follow chart 400may be automatically performed at regular time intervals. Alternatively,the user may initiate the processes in the flow chart 400.

The air-cooled devices described in conjunction with FIGS. 2A-4 changethe direction of air flow from a first direction to a second directionso as to optimize the cooling. However, it is noted that the firstdirection of the air flow may not be necessarily opposite to the seconddirection of the air flow. In embodiments, the first direction may bedifferent from the second direction, but may not be opposite to thesecond direction.

In embodiments, one or more computing system may be configured toperform one or more of the methods, functions, and/or operationspresented herein. Systems that implement at least one or more of themethods, functions, and/or operations described herein may comprise anapplication or applications operating on at least one computing system.The computing system may comprise one or more computers and one or moredatabases. The computer system may be a single system, a distributedsystem, a cloud-based computer system, or a combination thereof.

It shall be noted that aspects of the present disclosure may beimplemented in any instruction-execution/computing device or systemcapable of processing data, including, without limitation phones, laptopcomputers, desktop computers, and servers. The present disclosure mayalso be implemented into other computing devices and systems.Furthermore, aspects of the present disclosure may be implemented in awide variety of ways including software (including firmware), hardware,or combinations thereof. For example, the functions to practice variousaspects of the present disclosure may be performed by components thatare implemented in a wide variety of ways including discrete logiccomponents, one or more application specific integrated circuits(ASICs), and/or program-controlled processors. It shall be noted thatthe manner in which these items are implemented is not critical to thepresent disclosure.

Having described the details of the disclosure, an exemplary system 500,which may be used to implement one or more aspects of the presentdisclosure, will now be described with reference to FIG. 5. Eachdevice/equipment in FIGS. 2A-4 includes one or more components in thesystem 500. As illustrated in FIG. 5, system 500 includes a centralprocessing unit (CPU) 501 that provides computing resources and controlsthe computer. CPU 501 may be implemented with a microprocessor or thelike, and may also include a graphics processor and/or a floating pointcoprocessor for mathematical computations. System 500 may also include asystem memory 502, which may be in the form of random-access memory(RAM) and read-only memory (ROM).

A number of controllers and peripheral devices may also be provided, asshown in FIG. 5. An input controller 503 represents an interface tovarious input device(s) 504, such as a keyboard, mouse, or stylus. Theremay also be a scanner controller 505, which communicates with a scanner506. System 500 may also include a storage controller 507 forinterfacing with one or more storage devices 508 each of which includesa storage medium such as magnetic tape or disk, or an optical mediumthat might be used to record programs of instructions for operatingsystems, utilities and applications which may include embodiments ofprograms that implement various aspects of the present disclosure.Storage device(s) 508 may also be used to store processed data or datato be processed in accordance with the disclosure. System 500 may alsoinclude a display controller 509 for providing an interface to a displaydevice 511, which may be a cathode ray tube (CRT), a thin filmtransistor (TFT) display, or other type of display. System 500 may alsoinclude a printer controller 512 for communicating with a printer 513. Acommunications controller 514 may interface with one or morecommunication devices 515, which enables system 500 to connect to remotedevices through any of a variety of networks including the Internet, anEthernet cloud, an FCoE/DCB cloud, a local area network (LAN), a widearea network (WAN), a storage area network (SAN) or through any suitableelectromagnetic carrier signals including infrared signals.

In the illustrated system, all major system components may connect to abus 516, which may represent more than one physical bus. However,various system components may or may not be in physical proximity to oneanother. For example, input data and/or output data may be remotelytransmitted from one physical location to another. In addition, programsthat implement various aspects of this disclosure may be accessed from aremote location (e.g., a server) over a network. Such data and/orprograms may be conveyed through any of a variety of machine-readablemedium including, but are not limited to: magnetic media such as harddisks, floppy disks, and magnetic tape; optical media such as CD-ROMsand holographic devices; magneto-optical media; and hardware devicesthat are specially configured to store or to store and execute programcode, such as application specific integrated circuits (ASICs),programmable logic devices (PLDs), flash memory devices, and ROM and RAMdevices.

Embodiments of the present disclosure may be encoded upon one or morenon-transitory computer-readable media with instructions for one or moreprocessors or processing units to cause steps to be performed. It shallbe noted that the one or more non-transitory computer-readable mediashall include volatile and non-volatile memory. It shall be noted thatalternative implementations are possible, including a hardwareimplementation or a software/hardware implementation.Hardware-implemented functions may be realized using ASIC(s),programmable arrays, digital signal processing circuitry, or the like.Accordingly, the “means” terms in any claims are intended to cover bothsoftware and hardware implementations. Similarly, the term“computer-readable medium or media” as used herein includes softwareand/or hardware having a program of instructions embodied thereon, or acombination thereof. With these implementation alternatives in mind, itis to be understood that the figures and accompanying descriptionprovide the functional information one skilled in the art would requireto write program code (i.e., software) and/or to fabricate circuits(i.e., hardware) to perform the processing required.

It shall be noted that embodiments of the present disclosure may furtherrelate to computer products with a non-transitory, tangiblecomputer-readable medium that have computer code thereon for performingvarious computer-implemented operations. The media and computer code maybe those specially designed and constructed for the purposes of thepresent disclosure, or they may be of the kind known or available tothose having skill in the relevant arts. Examples of tangiblecomputer-readable media include, but are not limited to: magnetic mediasuch as hard disks, floppy disks, and magnetic tape; optical media suchas CD-ROMs and holographic devices; magneto-optical media; and hardwaredevices that are specially configured to store or to store and executeprogram code, such as application specific integrated circuits (ASICs),programmable logic devices (PLDs), flash memory devices, and ROM and RAMdevices. Examples of computer code include machine code, such asproduced by a compiler, and files containing higher level code that areexecuted by a computer using an interpreter. Embodiments of the presentdisclosure may be implemented in whole or in part as machine-executableinstructions that may be in program modules that are executed by aprocessing device. Examples of program modules include libraries,programs, routines, objects, components, and data structures. Indistributed computing environments, program modules may be physicallylocated in settings that are local, remote, or both.

One skilled in the art will recognize no computing system or programminglanguage is critical to the practice of the present disclosure. Oneskilled in the art will also recognize that a number of the elementsdescribed above may be physically and/or functionally separated intosub-modules or combined together.

It will be appreciated to those skilled in the art that the precedingexamples and embodiment are exemplary and not limiting to the scope ofthe present disclosure. It is intended that all permutations,enhancements, equivalents, combinations, and improvements thereto thatare apparent to those skilled in the art upon a reading of thespecification and a study of the drawings are included within the truespirit and scope of the present disclosure.

What is claimed is:
 1. An air-cooled electronic device, comprising: anair flow generator that is able to generate an air flow in first andsecond directions through the device, the first direction beingdifferent from the second direction; at least one sensor that measures afirst temperature of air in the air flow when the air flow is in thefirst direction and a second temperature of air in the air flow when theair flow is in the second direction; and a controller communicativelycoupled to the air flow generator and the at least one sensor, thecontroller: causing the air flow generator to generate the air flow inthe first direction and receiving the first temperature; causing the airflow generator to generate the air flow in the second direction andreceiving the second temperature; and comparing the first temperature tothe second temperature and controlling the air flow generator togenerate the air flow in one of the first and second directions based oncomparison of the first temperature to the second temperature.
 2. Theair-cooled electronic device as recited in claim 1, wherein the air flowgenerator includes at least one fan and a rotational direction of the atleast one fan is reversed to change a direction of the air flow.
 3. Theair-cooled electronic device as recited in claim 1, further comprising:at least one vent that forms a passageway of the air flow and allows afluid communication between the device and air surrounding the device.4. The air-cooled electronic device as recited in claim 1, wherein, whenthe air flow is in the first direction, the air flow generator pulls inthe air through the at least one vent and discharges the air to anoutside of the device.
 5. The air-cooled electronic device as recited inclaim 1, wherein, when the air flow is in the second direction, the airflow generator pulls in the air through the air flow generator anddischarges the air inside the device to an outside of the device throughthe at least one vent.
 6. A method for cooling an electronic device thathas an air flow generator, the method comprising: (a) causing the airflow generator to generate an air flow in a first direction andmeasuring a first temperature of air in the air flow; (b) causing theair flow generator to change the air flow to a second direction andmeasuring a second temperature of air in the air flow, the seconddirection being different from the first direction; (c) upon comparisonof the first temperature to the second temperature, selecting one of thefirst and second directions; and (d) causing the air flow generator togenerate the air flow in the selected direction.
 7. The method asrecited in claim 6, wherein the second direction is opposite to thefirst direction.
 8. The method as recited in claim 6, wherein a userinitiates the steps (a)-(d).
 9. The method as recited in claim 6,wherein the steps (a)-(d) are automatically repeated at regular timeintervals.
 10. The method as recited in claim 6, further comprising:sending a notification when the air flow generator changes a directionof the air flow.
 11. The method as recited in claim 10, wherein thenotification includes a simple network management protocol (SNMP) trap.12. An information handling system, comprising: an air flow generatorthat is able to generate an air flow through at least part of theinformation handling system; at least one sensor that measures airtemperature; and a controller communicatively coupled to the air flowgenerator and the at least one sensor, the controller configured toperform a method comprising the steps of: causing the air flow generatorto generate the air flow in a first direction and obtaining a firsttemperature from the at least one sensor when the air flow is moving inthe first direction; causing the air flow generator to generate the airflow in a second direction and obtaining a second temperature from theat least one sensor when the air flow is moving in the second direction,the second direction being different from the first direction; comparingthe first temperature to the second temperature; and responsive to thecomparison, selecting one of the first and second directions and causingthe air flow generator to generate the air flow in the selecteddirection.
 13. The information handling system of claim 12, wherein thesecond direction is opposite to the first direction.
 14. The informationhandling system of claim 12, wherein a user causes the controller toperform the method.
 15. The information handling system of claim 12,wherein the controller performs the method automatically at timeintervals.
 16. The information handling system of claim 12, wherein thecontroller is further configured to perform the step comprising: sendinga notification when the air flow generator changes a direction of theair flow.
 17. The information handling system of claim 16, wherein thenotification includes a simple network management protocol (SNMP) trap.18. The air-cooled electronic device of claim 1, wherein the controllerperforms, according to a schedule, the steps of: causing the air flowgenerator to generate air flow in the first direction and receiving thefirst temperature; causing the air flow generator to generate air flowin the second direction and receiving the second temperature; andcomparing the first temperature to the second temperature andcontrolling the air flow generator to generate the air flow in one ofthe first and second directions based on comparison of the firsttemperature to the second temperature.
 19. The air-cooled electronicdevice of claim 1, wherein the controller is further configured toperform the step comprising: sending a notification when the air flowgenerator changes a direction of the air flow.
 20. The air-cooledelectronic device of claim 19, wherein the notification includes asimple network management protocol (SNMP) trap.